The present invention relates to air treatment filter elements and air treatment filters. Specifically, the invention relates to air treatment filter elements and air treatment filters for removing odors and harmful gases from indoor air.
As is well-known, indoor air often contains numerous pollutants, including formaldehyde, acetic acid, ammonia, hydrogen sulfide, sulfur dioxide and solvent gases such as benzene and toluene. Recently, a great deal of attention has been given to formaldehyde pollution as a result of U.S. government studies linking formaldehyde to cancer. Further, indoor air often contains numerous odors, such as bathroom odors, kitchen odors, basement odors and tobacco odors.
In the past, air treatment systems have employed special liquids for removing odors and inhibiting the growth of micro-organisms, many of which are odor causing. While many air treatment systems have been effective to deodorize, such systems have lacked both high capacity and high efficiency for removing pollutants such as formaldehyde and solvent gases from air.
In attempting to increase the capacity and efficiency of air treatment systems for removing formaldehyde and solvent gases from indoor air, adding either activated carbon or zeolite (molecular sieves) to existing liquid containing air treatment systems has not been considered practical because it would be expected that contact of activated carbon and zeolite with a liquid for removing odors and inhibiting the growth of microorganisms would poison the gas adsorption properties of both the activated carbon and the zeolite. Specifically, it was believed that the activated carbon and zeolite would be preferentially saturated with the liquid and thereby rendered useless for adsorbing gases.
Consequently, it was believed necessary to redesign existing air treatment systems to contain separate compartments for the air treatment liquid and the activated carbon and zeolite so that no contact of the liquid with activated carbon and zeolite would occur. Obviously, the redesign of an existing system would be complicated, time consuming and expensive.
In accordance with the present invention, however, it has been found that the combination of certain air treatment liquids with activated carbon and zeolite does not destroy the gas adsorption properties of the activated carbon and zeolite. Totally unexpectedly, it has been discovered that not only does the liquid fail to poison the zeolite and activated carbon, but that the liquid-treated zeolite and activated carbon in fact adsorbed higher percentages of formaldehyde than untreated zeolite and activated carbon. Further, it was unexpectedly discovered that applying the liquid to the zeolite and activated carbon can even increase the odor and gas adsorbing lives of zeolite and activated carbon.
The present invention provides air treatment filter elements and air treatment filter systems having increased capacity and efficiency for adsorbing formaldehyde, hydrogen sulfide, sulfur dioxide, solvent gases and other harmful gases from air, particularly from indoor air. Furthermore, zeolite and activated carbon containing filter elements are provided in which the activated carbon and zeolite have enhanced abilities to adsorb formaldehyde and increased odor and gas adsorbing lives.